Centerless grinding machine



Dec. 10, 1935. H. H. ASBfiIDGE 2,023,720

CENTERLESS GRINDING MACHINE Filed Aug. '7, 1931 4 Sheets-Sheet l Dec. 10, 1935. ASBRlDGE 2,023,720

GENTERLESS GRINDING MACHINE Filed Aug. 7, 1931 4 Sheets-Sheet 2 F l o! L H, H. ASBRIDGE CENTERLESS GRINDING MACHINE Filed Aug. 7, 1951 4 Sheets-Sheet 5 Dec. 10, 1935. H, A R E 2,023,720

CENTERLES S GRINDING MACHINE Filed Augf'7, 1931 4 Sheets-Sheet 4 By WW Patented Dec. 10, 1935 UNITED STATES FATENT OFFICE CENTERLESS GRINDING MACHINE Application August 7,

1931, Serial No. 555,802

In Great Britain August 14, 1930 Claims.

This invention relates tocenterless grinding machines of the type comprising a grinding wheel, a regulating wheel by which the rate of rotation of the workpiece is controlled, and awork- 5 support disposed between the grinding and regulating wheels, such support being movable towards the grinding wheel under the pressure of the regulating wheel engaging the workpiece thereon.

The object of my present invention is to provide an improved machine of the said type adapted for the convenient, rapid and economical production of workpieces which have to be machined in two stages or operations and in which the two machines portions have to be co-axial and true with one another. Bushes or tubes are examples of such workpieces, where it is required to produce a peripheral surface concentric with the hole through the bush which has been finished in a prior operation (that is, to produce bushes and the like with a wall of uniform thickness). Other examples of workpieces with the two machined parts in line but of different diameter will be shown in the accompanying drawings. 1

The invention comprises the improved combinations and arrangements of parts hereinafter described and claimed.

In the accompanying explanatory drawings:

Figure 1 is an end view of a centerless grinding machine having its operative parts arranged in accordance with my invention. A workpiece is shown upon the arbor at the commencement of the grinding operation.

Figure 2 is a View of the machine showing the workpiece at the end of the grinding operation.

Figure 3 is a plan View showing the grinding and regulating wheels and workpiece in the positions they occupy in Figure 2.

Figure 4 is a detail end view of the pivotally mounted work supporting bracket.

Figure 5 is a detail front view showing the stops for the handle by which the regulating wheel is moved towards and away from the grinding wheel.

Figure 6 is a View similar to Figure 4 showing a hollow arbor upon the worksupport to receive a cylindrical extension upon the workpiece, such extension having been previously machined and being a working fit in the arbor.

Figure 7 is a view similar to Figure l, and Figure 8 a view similar to Figures 4 and 6 but showing a work support in the form of a slide.

Figure 9 is a View similar to Figures 4, 6 and 8, and Figure 10 a plan view of Figure 9 showing a work supporting slide with means for reciprocating the same in the direction of the axis of the arbor upon the slide.

Figure 11 is a view similar to- Figures 4, 6, 8 and 9 but drawn to a larger scale, Figure 12 an end view similar to Figure 1 also drawn to a larger 5 scale, and Figure 13 an end View looking from right to left of Figure 11 showing ejector mechanism for removing the workpiece from its arbor automatically. Figure 14 is a sectional view on the line l4--l4 of Figure 11.

In Figures 1-5, ct indicates the grinding wheel carried in suitable bearings upon the machine bed 12; 0 indicates the regulating wheel mounted upon a slide 0! movable upon a lower slide e which itself is movable upon slideways upon the bed I).

1 indicates the work supporting bracket which is fulcrumed about a pin g carried by the slide e. Adjustable screwed studs h and i serve as abutments or stops to limit the pivotal movements of the bracket 1 towards and away from the grinding wheel a. A spring 7 acting upon the bracket tends to move it so that the stop i is in service or the workpiece is against the regulating wheel 6.

The slide e can be locked tothe bed b by a looking screw 7c and the slide 01 can be locked to the slide e by a similar screw 1.

Movement of the slide (1 can be effected in either of two ways. It can be efiected by turning the screw m by the handles or spokes m or by turning the handle it which has a threaded 30 1 sleeve thereon acting as a nut for the screw m, such sleeve being capable only of rotary movement in the slide d. When the handle n is in use, the screw m is locked by a screw 1', turned by the handle r Stops o and 9 limit the movement of the handle n.

Upon the bracket 1 is secured an arbor 8 upon which each workpiece can be placed from one end. The arbor is so positioned that the axis of the workpiece to be ground is above the plane 0 containing the axes of the grinding and regulating wheels. The arbor is a working fit within the bore of the workpiece. There may be a clearance of say 5/ 1000ths of an inch between the arbor and the bore of the workpiece which 45 permits of easy insertion and withdrawal of the workpiece by hand.

The operation of the machine is as follows:-

The machine is set to bring the fulcrum pin 9 to any desired distance from the grinding wheel 50 according to the diameter of work to be operated upon by locking the slide d to the slide e and turning the screw m. The regulating wheel is now set so as to get its range of movement between desired limits by locking the slide e to the 55 grinding and regulating wheels with its axis parallel to the axes of the said wheels.

What I claim is:

1. In centerless grinding machines, the combination of a grinding wheel and a regulating wheel both rotating in the same circular direction each having cylindrical working surfaces and disposed with their axes parallel one to the other, a work support, a work-piece carrying arbor mounted upon said work support at such a height that the arbor axis is not in the plane containing the axes of the said grinding and regulating wheels, the said arbor receiving as a loose Working fit and constituting the sole support for the workpiece which comes between the grinding and regulating wheels and is free to rotate about the axis of the arbor irrespective of any rotation of the arbor itself and which is engaged by the said regulating wheel to move said arbor towards said grinding wheel, a slide carrying said work support, a slide carrying said regulating wheel and movable upon the former slide, and means to position said slides relatively one to the other and to the grinding wheel.

2. In centerless grinding machines, the combination claimed in claim 1, combined with a pivotal mounting of the work support a stop to limit the movement of said work support towards said grinding wheel, and a spring to cause said work support to move away from said grinding wheel upon withdrawal of said regulating wheel, and a second stop to limit the movement of said work support towards said regulating wheel so that said work support is clear of said grinding and regulating wheels to facilitate removal of said work piece from said arbor.

3. For centerless grinding machines comprising in combination a grinding wheel and a regulating wheel each having cylindrical working surfaces, and disposed with their axes parallel one to the other, a regulating wheel slide and a 5 machine bed, an attachment comprising in combination a lower slide for slidably securing upon said machine bed below said regulating wheel slide, a work-support carried by said lower slide and movable towards and away from said grinding wheel and said regulating wheel, a workpiece carrying arbor non-rotatably mounted upon said work-support and adapted to receive as sole support workpieces which are free to rotate about the axis of said arbor, stops limiting the movement of said work-support in both directions and spring means tending to move said worksupport in one of said directions.

4. In centerless grinding machines the combination claimed in claim 1 combined with a stop to limit the movement of said work support towards said grinding wheel and an additional stop acting between the regulating wheel head and the work support whereby any twisting strain on the workpiece due to the regulating wheel when the first mentioned stop prevents further movement towards the grinding wheel is avoided.

5. In centerless grinding machines, the combination claimed in claim 1 combined with a movable support carried by said work support and adapted to take up one position in which it contacts with and supports said arbor at a point clear of said workpiece and another position in which it is distant from said arbor.

HARRY HALES ASBRIDGE. 

